Oscillator control circuit



April 20, 1948. D. L. HlNGS 7 2,

' OSCILLATOR CONTROL CIRCUIT Filed May 3, 1944 OUTPUT POWER VARIABLE CONTROL VOLTAGE DEV IC E Fig. :1.

3 OUTPUT POWER VARIABLE comm.

VOLTAGE DEVICE VARIABLE CONTROL VOLTAGE I DEVICE Patented Apr. 20, 1948 n music: STATES? mates Dona1d.L.-. Hings,;;ttawa, ifintarioa canad Application Majy, 3,;1944, Seg 'au I -C nada A fz i i 1. 9 Claims (Cl. zeta-sen;

My invention relates in generalto-radio fre-- I quency circuits and more particularly to circuits for controlling the oscillations ofan oscillatortube. 1

An. object of my-invention istto provide for starting and stopping-a l crystal oscillator-at high speedsp-- FY r Another: object of-my invention is to provide for. switching crystals without.mechanicalmeanst Another object of my invention is toprovidefor contro g. .an oscillator. with .a. multiple. of zotiodechoke I I .andithecintermediate. portion .ofthe swamping resistancecfl imayhe connected. to.-..

gather; .Theacontrobigrid; I5. is. bypassed to ground,- for; radimjrequencmthrough .a capacitor ysta-lsm Another object, of; my invention ::is .to. provide 1 for, the remote control of theselectionof crystals.... thoutmech nicai means.

hfir Object of H st-invention is toprevent; 25-

cr oad ng" of c ta -in.an oscillatolt.

Another objQCt of my inventiomis, to permit: more than one crystal to oscillate witlr'a,;in%1 oscillating tube.

, 211 a griddeak =7. ll Between-the plate 5- and the contrblwg queny dtermined by the characteristics of the crystal- 2 I 5 The plate 5 o'f the oscillator-tube 2i! is arranged 'toLdeliver-power to any suitable load as indicated-by the arrowl I The con-tro'l tube' "I 9 comprises a cathode I l, a control grid 45am a plate -I 6 -:vvhich islconnected to tHe upp'epside of-ithe variable-voltage .feeda baclc capaciton 64 The cathode: I 41 is. connected tothe opposit sideof thewvariablesvoltage feed- ;loack capacit0r -6. "TheLcathodeL I 4.. is maintained at r'adioifretiuencyzpotentials above ground. .by

mean'so'f the combinationtof acathode choke. I I

having in parallel therewith;asswampinglresistance I 1.1" 'Thecintermediatewportion of..the oath.-

l2'..: Theicontr'olgriddiiisgoverned by avariable control; voltagexlevicc indicatedby the. reference character 23.

Under; thecondition oiioperation to render the oscillator tuber?!) operativecfqrlgenerating a radio frequenctztas adeterminem birethc. chara t ristics Anotherobject of my invention provi s ,fOr "of"the crysta la2lathecontrulfirid;I5 is biased to ppinean r nea cr s al;o c atorl ith utl changingthe supply potentials to the. tube, 1.

Otherplojects and a fuller understandingoi my;

inventionmay be had by referring to the follow s. d t n an imsa en.- i c niunctionl-ise- With;the accompanying drawingin which,

Figure v1 isa circuitemhodying the features; of; t-in tion Figure 2,.=is a circuitshowingan extenslon ofr;

the circuitin Figural. 40.

With reference to ;Figure 1, my. circuit; com-1; p is sse era an. c t r u e fl rwh chc-is t ol er-t a n ol. ube he oscil ator; tube comprises a cathode. 2,-, ;a control grid 3,-

a en d andaplate 5. 'I'heplatej is-con f nectedto the positive potential-.of a direct our: rent source through a plate choke 9-which ;ha5:.a. swamping resistance I 0 connected parallel there: with. .The screengrid 4 is. connected to the."

positive potential Of 'the, direct current .S0 l TQ;, ;-v

The cathode 2 isconnected-tothe negative pqtcnz tial of the direct current-source; The screen grid 9 "is Icy-passed to. ground-throu h .the canes-.1

a batt ry l 8 :which is; connectedin: series with..:.. 5

cut-40th.- 1112017151617; words,.:when; the nt grid thatathe capac torzfizzand the-c s alz I operate su stantialhtthe sam sa il he c nt o e r notninicthe; circuit Accordingly; the; oscillator tuhedhfunctimshto:nr duce ;.osci 1ati nswhich a ee yenned.supstantiallvsolely :t e pac tor 6 andthe:cry.s.ta1.--2I12;v

rednceith is d more. pQSitive through t issflmdi ibmlQHZI QQQQW .1 he e-t0- p atetcircuit-= nthelc ntrolltu el 9 andimpresses a vo tagezin npq sitecphase; pon the; f ed-back.

a acito. .6 which-tends no-neutra ise, dba l ;-energv;,. eli. erred to: thec pac t r by t e os-. latorzz ircui The 1a.tQ b is ran adrtolbeg ndercd icomplc e vinoperative by asinathe tcontrola ridnl 5;;t0 a-pred t r p sitive tblasi-bv the Nariab1e= ontro1 voltage .de-

id-1:15 wh r bypt e;neut a isin efl t po ed 3, I prowdeformounting a crystal; 2 I

and a variable -voltage-feed-back-- capacitor 6 which rearranged-rte be adju'stablec Theoscila labor asdescribed-,-will-oscillate at a fre- Tc render thacwilhtor t bei 0. in p e trengthgo fythcr oscillations, thea eevice; 23, Under upon the capacitor 6 is not completely cancelled, with the result that the oscillator tube 20 oper ates with a reduced amplitude.

The variable control voltage device may include a number of arrangements depending upon the use to which my circuit is employed. Thus for example the bias of the control grid may be governed by any one of the following arrangements; namely, by a. telegraph key; by a telegraph key with tone modulating waves; by voice modulating waves; by voice modulating waves with voice control bias; and by frequencies of- 1 any wave form. Each of these variable control.

voltage devices may be located at aremote point from the terminals A and B which enables me to.

obtain control of the control tube by. remote operation. With reference to a telegraph key,

of the crystal 5| when the variable control voltage device-between A and C is operated. Under one set of circuit conditions, the oscillator tube "oscill'ates in accordance with the characteris- V .tics of the crystal 2|. Under a second set of conditions the oscillator tube 20 oscillates in accordeach time that the operator depresses the key the V bias on the control tube l5 becomes more"nega-,

tive and permits the crystal 2| to oscillate. For telegraph key with tone modulating waves, the control grid |5 is first biased negative upon the key being depressed, after which the-crystal 2| oscillates atamplitudes governed by the-tone generator. For voice modulating waves, the control grid |5 is biased so that the crystal oscillates at a limited amplitude which is varied'by voice modu lating waves. For voice modulating waves with voice control bias, the control grid -.|5 receives in combination voice modulatingwaves and result ing negative bias from rectifications of these waves which permits the crystal to start oscillating and to vary. in amplitude with the modulating waves simultaneously. positive with the termination of the modulating waves which stops the crystal oscillating. In

other words this arrangement is characterized as.

a voice operated carrier.

In addition to controlling the oscillations of the oscillator tube 2|), the control tube|9 functions to limit or regulate the voltage impressed upon the crystal 2|, This regulation is brought about through the circuit arrangement between.

the crystal 2| and thecontrol grid: |5,. inthat when the voltage amplitude upon the crystal 2| tends to become too great by means or varying load values, the control grid l5 becomes operative cathode I4 and thereby causes thecontrol tube l9 to pass current and impressavoltage inopposite phase upon the capacitor 6 to decreasethe voltage thereon which in' tum limits thevoltage impressed upon the crystal 2|. i

In Figure 2 I show an extension of the circuit in Figure 1, whereby the oscillator tubeZO is gov- I erned by two crystals. The portion of thecircuit to the right of the vertical-dotted line is substantially the same as that shownin Figure land the 1 The bias returns because of the increased cathode voltage on'the portion of the circuit to the left of the vertical dotted line represents theadded part. '-'The portical line is designated by the reference character d9 which is higher than the reference character I9 by a value of 30. The control grid IS in Figure 2 is controlled by the variable control voltage 'de- Vice between A and B and the control grid 45 or the control tube 49 isgoverned by the variable i control voltage device between A'and C.- The ance with' the characteristics of the crystal 5|. Under another set of conditions the oscillations of the oscillator tube may be stopped when both of the crystals 2| and 5| are made inoperative by their respective control tubes, and under a fourth condition the oscillator tube 20 may oscillate simultaneously at two frequencies which are governed respectively by the crystals 2| and 5|.

While I have shown in Figure 2 two variable control voltage devices; namely, between A to B and Ato C, it is to be understood my system may be extended to include a larger number of such variable control voltage devices together with their related control tubes and crystals. The operation of the crystals 2| and 5| are independent of each other and their frequency values may be relatively close or far apart or they may be of the same frequencies. The fast alternation or interchange of crystals permits multiplex operation when individually operated in groups of pulses. This arrangement does not require synchronization 'atthe receiving point;

Although I have shown and described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and thescope of the invention as hereinafter claimed.

I claim as my invention: 1. A radio frequency system comprising an oscillator circuit including at least an oscillator tube, saidoscillator tube having at least a cathode, a plate and a control element, said cathode being connected to a point of reference'potential, impedance means connected between said plate and said point of reference potential, a crystal and a capacitor connected in series between th plate and the control element for controlling the oscillations of the oscillator tube, said capacitor having a first terminal connected to said late and a second terminal connected to said crystal, 9. control tube having at least a cathode, a plate and a control element, means including impedance means'for connecting the cathode of the control tube to said point of reference p tential, first circuit means for connecting the plate of the con trol tube to the first terminal of the capacitor, second circuit means for connecting the cathode of the control tube to the second terminal of the capacitor, and variable voltage means for varying the bias of the control element of the control tube and thereby governing the oscillationsof the oscillator tube.

2. A'radio frequency system comprising an oscillator circuit including at least an oscillator tube having at least'plate, cathcde'and control elepoint"? ofreference potential,firstrreactance' means connected. between said; plate :element and said point of: reference potential, secondreac'tance means connected between two of said three elements-and subject t'oa feedbackzvoltage to'sust'ain' oscillation; a control tube.- having: at a least anode, cathode "and control means; means including im. pedance means forconnectingthecathode means to said point of reference potential, connection meansfor connecting said second reactance means across said anode-and cathode means, and variable voltage means for varying the bias of the controlmean ithereby governing the oscillations of the oscillator tube.

3. A radio frequency systemcomprising an oscillator circuit including at least an oscillator tube having at least plate, cathode and control ,elements, said cathode element being connected to a point of reference potential, first reactance meansconnected between said plate element and said point of reference potential, a crystalggsecon'd reactance means connected in series;;with said: crystal across two of said three elementsand subject to a feedback Voltage to sustain-oscillation", a control tube having at least anode, cathode and control means, means including impedance means for connecting the cathode means to said point of reference potential, connection; means for connecting said second reactance means across said anodeand cathode means, and variable voltage'means for varying the bias of the control means thereby governing the oscillations of the oscillator tube, a

4. A radio frequency system comprising an oscillator circuit including at least an oscillator tube having at least plate, cathode and control elements, said cathode element being connected to a point of reference potential, reactance means connected between said plate element and said point of reference potential, a crystal, capacitance means connected in series with said crystal across two of said three elements and subject to a feedback voltage to sustain oscillation, a control tube having at least anode, cathode and control means, means including impedance means for connecting the cathode means to said point of reference potential, connection means for connecting said capacitance means across said anode and cathode means, and variable voltage means for varying the bias of the control means thereby governing the oscillations of th oscillator tube.

5. A radio frequency system comprising an oscillator circuit including at least an oscillator tube having at least a cathode, a plate and a controle element, said cathode being connected to a point of reference potential, a first impedance device connected between the plate and the point of reference potential, a branch circuit including a second and a third impedance device for interconnecting said cathode, plate and control element, said second impedance device having a first and second terminal, first connection means for connecting said first terminal of the second impedance device to the said plate, second connection means for connecting the said second terminal of the second impedance device to the said control element, third connection means for connecting the said third impedance device between the second terminal of the second impedance device and the point of reference potential, a control tube having at least a cathode, a plate, and a control element, first circuit means for connecting the plate of the control tube to the first terminal of the second impedance device, second circuitrmeans; for connecting the. cathode of the contr lit'llbe to the;-secondrterminaiort e se n impedancedevica,andavariable voltage means for varying; the: bias 'ofa-the control element of the control; tube: and thereby govern the oscillations ofzthe; oscillator tube,

. 6.. A radio frequency system, comprising an oscillator: circuit, including; at least an oscillator tube having at least-a cathode, aplate-and acontrol element, said: cathode being connectedtto a point: ofqreference potential, a first impedance device:connected-betwegm the plate and the-point ofrreference potential, a. branch circuit including a; crystal, anda second and a third impedance device for: interconnecting said cathode, plate and control: element, said second impedance device having a: first. and second terminal-, first connection means forconnecting said firsttermiml of thesecond impedance. device, to the said plate, :second connection:,means for connecting the said crystalbetween the second terminal of the second'impedance device andv the said control element, third; connection, means for connecting the said third impedancedevicebetween the second; terminal :of: the second impedance device. and the-point of reference potc 1& a control tube :having at lea-st a cathode; ,a plate, and a control: element, first :circuit means-for connectingnthe plateof the control tube to the first terminal of the second impedance device, second-circuit means for connecting the cathode of the control tube to the second-terminal of the second impedance device, .and variable voltage meansfor varying the bias of'the-controlelement ofithe controlxtube and thereby govern theoscillations of the oscillator tube.

"7. A radio frequency system comprising an oscillator tube having a plate, a cathode, a control grid and a screen grid, first impedance means connected between said screen grid and c said plate, direct current potential means connected to said screen grid, said cathode being connected to a point of reference potential, first oscillator frequency by-pass means connected between said screen grid and said point of reference potential, a capacitor and a crystalconnected in series between said plate and said control grid, said capacitor having a first terminal connected to said plate and a second terminal connected to said crystal, second impedance means and biasing means connected between said control grid and said cathode, a control tube having anode means, cathode means and control means, connection means for connecting said capacitor across said anode and cathode means, means including third impedance means for connecting said cathode means to said point of reference potential, second oscillator frequency by-pass means connected between said control means and said point of reference potential, and variable voltage means connected across said second oscillator frequency by-pass means.

8. A radio frequency system comprising an oscillator circuit including at least an oscillator tube, said oscillator tube having at least a cathode, a plate and a control element, said cathode being connected to a point of reference potential, impedance means connected between said plate and said point of reference potential, 2, first and second crystal and a first and second capacitor, first connection means for connecting said first crystal and capacitor in series between the plate and the control element for controlling the oscillations of the oscillator tube, second connection means for connecting said second crystal and capacitor in series between the plate and the control element ior' controlling the oscillations of the oscillatortube, said capacitors having a first terminal connected to said plate and a second terminal connected to said correspondingly numbered crystals, first and second control tubes having at least a 'cathode, a plate and a control element, means including impedance means for connecting the respective cathodes of the control tubes tosaid point of reference potential, first circuit means for connecting the plates of the control tubes to the first terminals of the capacitors, second circuit means for connecting the cathodes of the control tubes to the second terminals of the respective capacitors, and first and second variable voltage means for varying the bias of the control elements of the first and second control tubes, respectively, said first and second control tubes being also con-' trollably operable simultaneously by the first and second variable voltage means for. controlling the oscillations of the oscillator tube.

9. A radio frequency system comprising an oscillator circuit including at least an oscillator tube having at least cathode, plate and control elements, said cathode being connected to a point of reference potential, first reactance means connected between said plate element and said point of reference potential, second and third reactance means connected in parallel between two of said three elements and subject to a feedback voltage to sustain oscillation, first and second control tubes each having at least anode, cathode and control means, means including impedance means for connecting the respective cathode means to .the said point of reference REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,559,116 Marrison Oct. 27, 1945 1,578,296 Taylor Mar. 20, 1926 1,919,993 Tripp July 25, 1933 1,985,104 Osnos Dec. 18, 1934 1,999,656 Goddard Apr. 30, 1935 2,054,431 Lindenblad Sept. 15, 1936 2,071,564 Nicolson Feb. 23, 1937 2,133,648 Pierce Oct. 18, 1938 2,225,691 Finch Dec. 24, 1940 2,282,103 7 Tunick May 5, 1942 2,288,486 Rivlin June 30, 1942 2,298,438 Usselman Oct. 13, 1942 2,306,555 Mueller Dec. 29, 1942 2,343,099 Usselman Feb. 29, 1944 

